THE PROBLEM OF SEX IN PLANTS 
347 
entire new plant. A leaf of begonia laid on moist sand 
will give rise to several new plants wherever it is cut (Fig. 
254). Leaves of the sundew (Drosera) frequently strike 
FIG. 253. Regeneration at the leaf-base of potato leaves (Sdanum 
luberosum). a, roots formed; b, tuber-like enlargement; c, same as b, 
with roots; d, formation of true tuber. (After Miss Elsie Kupfer.) 
FIG. 254. Young plantlets developing from the edges of lacerations 
made in a large leaf of Rex begonia. ' 
root at the tip and develop new plants (Fig. 255), while 
the leaves of Bryophyllum normally produce marginal 
buds from which new plants develop (Fig. 256). As 
